In this paper, a primary lens of concentrator photovoltaic (CPV) system is designed by using freeform optics. The designed lens is constructed based on a basic idea of a combination of Fresnel lens and freeform optics...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
In this paper, a primary lens of concentrator photovoltaic (CPV) system is designed by using freeform optics. The designed lens is constructed based on a basic idea of a combination of Fresnel lens and freeform optics, in which the lens is divided into an array of sub-lenses, which are designed using the conservation of optical path length and the edge ray theorem to get uniform irradiance distribution over the receiver. In this design, every sub-lens is designed to guide the direct sunlight over the receiver with uniform irradiance so that the whole of the primary lens will converge uniformly the direct sunlight over the receiver. The structure of the lens is designed firstly by using Matlab program for every sublens. The Matlab data of the designed lens structure is then used to build the three-dimensional (3D) lens in LightTools (TM) software. The ray tracing technique in LightTools (TM) software is used to find out the optimum structure of the freeform lens. Furthermore, the simulation is performed to estimate the efficiency of the lens as a concentrator of a CPV system by using the light source with the sunlight spectrum. The designed lens can achieve high geometrical concentration ratio and uniform irradiance distribution over the receiver. The simulation results show that the lens can easily reach a high concentration ratio (494 times) with uniform irradiance distribution and good optical efficiency (86%).
Fluidic lenses offer tunability and flexibility that are not available with conventional solid lenses. The development of a variable focus lens has the potential for replacing bulky optical systems and allows the mini...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
Fluidic lenses offer tunability and flexibility that are not available with conventional solid lenses. The development of a variable focus lens has the potential for replacing bulky optical systems and allows the miniaturization of imaging optics used in digital cameras and mobile phone cameras. In this paper, a liquid lens platform for use in an undergraduate laboratory setting is presented. A variable lens is prepared by injecting water into bulk polydimethylsiloxane (PDMS) that remains uncured in its fluid state. We report the tunable focusing ability of this simple liquid lens system and analyze the change in focal length as a function of injected water volume. The water-PDMS interface acts as a diverging lens, in agreement with ray tracing analysis based on curvature and refractive indices. Variable focal lengths are measured with an optical set-up employing a helium-neon laser and a solid converging lens with focal length = 2.5 cm. By increasing the water volume from 0.05 to 0.30 ml, we are able to tune the focal length from -6.5 mm to -10.6 mm. lens geometry remains spherical as the curvature of the lens changes with the addition of water. Our experiments coincide with a simple theoretical framework for a thick lens immersed in a medium. The water-PDMS lens is a promising component of basic and advanced experiments in an undergraduate optics course.
The design of four mirrors anti-astigmatism astronomical telescope is carried out for low earth orbit satellite. By integrating with Cassagrain and Schwartzschild configurations, the telescope is design. It contains f...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
The design of four mirrors anti-astigmatism astronomical telescope is carried out for low earth orbit satellite. By integrating with Cassagrain and Schwartzschild configurations, the telescope is design. It contains four mirrors with conic surface, to form an aberration free. The system contains two parts: first part is the Cassagrain type telescope for pick up the ground object to the stop position, and the second part is Schwartzschild configurations as relay optics, which is to relay the image to high resolution CCD sensor to provide 0.5 ground space distance image. The system is symmetric with aberration free within a one cubic size fitted for small satellite. The optic mechanical is simple easy to assemble for optical calibration, while the body is rigid in space.
To compensate the spherical aberration of the eye using the conic constant of the first surface of a contact lens for different refractive errors. Refractive errors were simulated by modifying only the first curvature...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
To compensate the spherical aberration of the eye using the conic constant of the first surface of a contact lens for different refractive errors. Refractive errors were simulated by modifying only the first curvature of the cornea. For every refractive error was calculating Zernike polynomials using Optics Software for Layout and Optimization (OSLO) EDU edition with and without contact lens. To calculate the conic constant of the contact lens we use the Seidel sums for thin lenses from the longitudinal spherical aberration as it proposes V. Mahajan. The value of Zernike spherical aberration coefficient for the eye with farsightedness (+ 5.00 D) + spherical contact lens was 0.142691 mu m. The conic constant value to compensate the spherical aberration was -0.222995 and the value of Zernike spherical aberration coefficient of the eye + aspherical contact lens was 0.004354 mu m. The value of Zernike spherical aberration coefficient for the eye with myopia (- 5.00 D) + spherical contact lens was 0.144505 mu m. The conic constant value to compensate the spherical aberration was -0.101424 and the value of Zernike spherical aberration coefficient of the eye + aspherical contact lens was 0.072820 mu m. The proposed method allows us to design contact lenses that compensate for the spherical aberration of the eye from the Zernike polynomials. Although the design of contact lenses is to third order, we obtain a smaller spherical aberration than the chromatic aberration on the axis without use optimization routine.
A head-mounted display (HMD) requires a large field of view (FOV) and a large exit pupil diameter while maintaining a compact structure. In this paper, we show a head-mounted display design comprising two freeform mir...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
A head-mounted display (HMD) requires a large field of view (FOV) and a large exit pupil diameter while maintaining a compact structure. In this paper, we show a head-mounted display design comprising two freeform mirrors covering a 28 degrees full field-of-view with an eye relief of 15mm. The simplified partial differential equation (PDE) method is applied in the design of a two-mirror HMD system. Then the data points on the unknown freeform mirrors are calculated using the rays from multiple fields and are used to construct the freeform mirrors in the HMD system, which is taken as a starting point. This simplified partial differential equation method makes calculations easier. The anamorphic surface and the XY polynomial freeform surface are used in the two freeform mirrors for improving the image quality, respectively. The optimization strategy is also described in detail. The final HMD system operates at F/3.75 with 8mm exit pupil diameter achieving good imaging performance.
Directed energy propulsion for interstellar travel has been proposed as an ideal method for reaching appreciable speeds relative to the speed of light: 0.2c. However, the amount of energy required necessitates a large...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
Directed energy propulsion for interstellar travel has been proposed as an ideal method for reaching appreciable speeds relative to the speed of light: 0.2c. However, the amount of energy required necessitates a large aperture, on the order of kilometers, while mitigation of atmospheric perturbations requires a discretization of the aperture into many individual laser elements. The use of fiber lasers for these elements obligates mode-matching the fiber to the desired 10 cm aperture for a collimated beam. Various collimation systems were designed and compared. A 3-lens system with one achromat and two aspheric lenses, with two of the lenses used as a Keplerian telescope to achieve a system-shortening effect was analyzed. A similar system made with a plano-convex lens replacing the large-aperture aspheric lens with two additional compensating lenses was compared. A single diffractive optic operating at F/8 was likewise considered. The optical performance of these systems was compared, as was the cost-effectiveness. Scalability to millions of elements was required, so cost-per-system was a crucial consideration factor. Possible manufacturing processes for a diffractive system were investigated, and stamping processes for replication were analyzed to determine the possibility of replication of such an optic reliably, cheaply, and with acceptable results.
Minimal refractive index data in the near-infrared spectrum are available for optical plastics. Typically, refractive index measurements are made by fabricating a prism of candidate optical material and using appropri...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
Minimal refractive index data in the near-infrared spectrum are available for optical plastics. Typically, refractive index measurements are made by fabricating a prism of candidate optical material and using appropriate metrology equipment. Few plastics are available in thicknesses adequate to fabricate appropriate size prisms;however, almost all optical plastics can be acquired in a flat plate form. The investigation considered two fundamental approaches to measure the refractive index by (i) rotating a flat plate and measure the beam displacement and ( ii) measuring the optical focal shift. The rotation method was determined not accurate enough. An optical focal shift method optical(n = t(optical)/t(mechanical)) was developed that utilized existing laboratory equipment. The shift of focus when the plastic plate sample was inserted was located by determining the position of maximum contrast of the projection of a Ronchi ruling target when illuminated by flux from a Cary Eclipse covering the spectral range of 550-975 nm. The instrumentation, data processing, and measurement performance are presented.
In this paper, an efficient lighting design for indoor sport field is presented. The average illuminance for the indoor sport field with eight playing courts can be achieve to 500 lx at a 11.2 m of the lamp's moun...
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This paper reports on the exposure of visible wavelength camera optical elements to a simulated orbital radiation environment in support of the Restore-L flight project at NASA's Goddard Space Flight Center. Boros...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
This paper reports on the exposure of visible wavelength camera optical elements to a simulated orbital radiation environment in support of the Restore-L flight project at NASA's Goddard Space Flight Center. Borosilicate glasses with various metal oxide dopants - S-LAL8, S-LAL18, N-SF1, and the polycarbonate material Makrolon GP were exposed to electrons and protons of varying energies. Low energy (E <= 10keV) charged particles were used primarily to assess degradation to the antireflective coatings of the optical elements. High energy (E similar to 1 MeV) charged particles were used to evaluate degradation to the bulk material. Elements of S-LAL18, N-SF1, LaK9G15, and Makrolon GP were exposed to a representative atomic oxygen rich environment. Elements of S-LAL8 and Makrolon GP were exposed to intense ultraviolet radiation. Pre- and post-exposure transmittance measurements were used to quantify the effects on the elements tested in the simulated environment over the 0.3 to 1.2 micron wavelength range. Our measurement results will be discussed in the context of their robustness to the orbital environment and the known chemical constituents of the materials tested.
Fundus cameras are the current clinical standard for capturing retinal images, which are used to diagnose a variety of sight-threatening conditions. Traditional fundus cameras are not easily transported, making them u...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
Fundus cameras are the current clinical standard for capturing retinal images, which are used to diagnose a variety of sight-threatening conditions. Traditional fundus cameras are not easily transported, making them unsuitable for field use. In addition, traditional fundus cameras are expensive. Due to this, a variety of technologies have been developed such as the D-EYE Digital Ophthalmoscope (D-EYE Srl, Padova, Italy) which is compatible with various cellphone cameras. This paper reports on the comparison of the image quality of the Nidek RS-330 OCT Retina Scan Duo (Nidek, Tokyo, Japan) and the D-EYE paired with an iPhone 6 (Apple, Cupertino, USA). Twenty-one participants were enrolled in the study of whom 14 underwent nonmydriatic and mydriatic imaging with the D-EYE and the Nidek. Seven participants underwent nonmydriatic imaging with the D-EYE and the Nidek. The images were co-registered and cropped so that the region of interest was equal in both the D-EYE and Nidek images, as the D-EYE had a smaller field of view. Using the Nidek image as the reference, objective full-reference image quality analysis was performed. Metrics such as structural similarity index and peak signal noise ratio were obtained. It was found that the image quality of the D-EYE is limited by the attached iPhone camera, and is lower when compared to the Nidek. Quantification of the differences between the D-EYE and Nidek allows for targeted development of smartphone camera attachments that can help to bridge the current gap in image quality.
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